1. aGraduate Student (MS), Department of Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China
2. bChair and Professor in Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China
3. cProfessor in Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China